#define  _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;

class sum
{
public:
    sum()
    {
        _sum += _ret;
        _ret++;
    }
    static int getsum()
    {
        return _sum;
    }
private:
    static int _ret;
    static int _sum;

};

int sum::_ret = 1;
int sum::_sum = 0;

int main()
{
    sum a[2];
    cout << sum::getsum();

	return 0;
}